diff --git a/api/services/content/v1/content.proto b/api/services/content/v1/content.proto
index bafca9066..0c48a37ad 100644
--- a/api/services/content/v1/content.proto
+++ b/api/services/content/v1/content.proto
@@ -136,7 +136,6 @@ message StatusResponse {
 	Status status = 1;
 }
 
-
 message ListStatusesRequest {
 	string filter = 1;
 }
diff --git a/metadata/buckets.go b/metadata/buckets.go
index 51daceb2a..0ba3126bb 100644
--- a/metadata/buckets.go
+++ b/metadata/buckets.go
@@ -36,7 +36,7 @@ var (
 	bucketKeyObjectSnapshots  = []byte("snapshots")  // stores snapshot references
 	bucketKeyObjectContent    = []byte("content")    // stores content references
 	bucketKeyObjectBlob       = []byte("blob")       // stores content links
-	bucketKeyObjectIngest     = []byte("ingest")     // stores content links
+	bucketKeyObjectIngest     = []byte("ingest")     // stores ingest links
 
 	bucketKeyDigest    = []byte("digest")
 	bucketKeyMediaType = []byte("mediatype")
diff --git a/metadata/content.go b/metadata/content.go
index d7b2912df..74e6add54 100644
--- a/metadata/content.go
+++ b/metadata/content.go
@@ -296,6 +296,11 @@ func (nw *namespacedWriter) commit(tx *bolt.Tx, size int64, expected digest.Dige
 	if err != nil {
 		return err
 	}
+	if size != 0 && size != status.Offset {
+		return errors.Errorf("%q failed size validation: %v != %v", nw.ref, status.Offset, size)
+	}
+	size = status.Offset
+
 	actual := nw.Writer.Digest()
 
 	if err := nw.Writer.Commit(size, expected); err != nil {
@@ -307,8 +312,6 @@ func (nw *namespacedWriter) commit(tx *bolt.Tx, size int64, expected digest.Dige
 		}
 	}
 
-	size = status.Total
-
 	bkt, err := createBlobBucket(tx, nw.namespace, actual)
 	if err != nil {
 		return err
diff --git a/services/diff/service.go b/services/diff/service.go
index b97908ace..b4d1a150b 100644
--- a/services/diff/service.go
+++ b/services/diff/service.go
@@ -3,6 +3,7 @@ package diff
 import (
 	diffapi "github.com/containerd/containerd/api/services/diff/v1"
 	"github.com/containerd/containerd/api/types"
+	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/plugin"
 	"golang.org/x/net/context"
@@ -45,7 +46,7 @@ func (s *service) Apply(ctx context.Context, er *diffapi.ApplyRequest) (*diffapi
 
 	ocidesc, err := s.diff.Apply(ctx, desc, mounts)
 	if err != nil {
-		return nil, err
+		return nil, errdefs.ToGRPC(err)
 	}
 
 	return &diffapi.ApplyResponse{
@@ -60,7 +61,7 @@ func (s *service) Diff(ctx context.Context, dr *diffapi.DiffRequest) (*diffapi.D
 
 	ocidesc, err := s.diff.DiffMounts(ctx, aMounts, bMounts, dr.MediaType, dr.Ref)
 	if err != nil {
-		return nil, err
+		return nil, errdefs.ToGRPC(err)
 	}
 
 	return &diffapi.DiffResponse{
diff --git a/services/tasks/service.go b/services/tasks/service.go
index 63a273872..81bd61910 100644
--- a/services/tasks/service.go
+++ b/services/tasks/service.go
@@ -62,6 +62,7 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
+	cs := metadata.NewContentStore(m.(*bolt.DB), ct.(content.Store))
 	runtimes := make(map[string]runtime.Runtime)
 	for _, rr := range rt {
 		r := rr.(runtime.Runtime)
@@ -71,7 +72,7 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 	return &Service{
 		runtimes: runtimes,
 		db:       m.(*bolt.DB),
-		store:    ct.(content.Store),
+		store:    cs,
 		emitter:  e,
 	}, nil
 }
diff --git a/task.go b/task.go
index bfbaa6453..60f894686 100644
--- a/task.go
+++ b/task.go
@@ -346,7 +346,7 @@ func writeContent(ctx context.Context, store content.Store, mediaType, ref strin
 	if err != nil {
 		return d, err
 	}
-	if err := writer.Commit(0, ""); err != nil {
+	if err := writer.Commit(size, ""); err != nil {
 		return d, err
 	}
 	return v1.Descriptor{